This invention relates to a method for preparing new biodegradable foams. More particularly, the present invention provides new dental and biomedical foams using a hydrophilic polyurethane foam having a biodegradable moiety.
Numerous devices have been proposed in the prior art for use as dental and biomedical foams for absorbing or removing body fluids. Typically, the prior art approaches have relied upon natural materials such as cotton, which is now becoming relatively expensive while providing a resultant structure which is generally fragile in use. Also, the amount of absorption by natural materials is relatively low.
Various polyurethanes have been used as dental and biomedical foams but suffer a disadvantage in that such foams are not readily biodegradable. It has now been found, however, that by practice of the present invention, there is provided a method for preparing new, simple and highly efficient dental and biomedical foams which are readily biodegradable after use, and which are characterized by high absorptive ability of body fluids in use.
Various attempts have also been made in the prior art to prepare foams of organic substances for use in cavities of the human body. However, such organic substances typically require, for example, catalysts or the like during the foaming reaction. These additives remain in the foam after foaming and are readily leached into the human body when in contact with body fluids. Thus, although artificial foams, especially those of polyurethane, of the prior art possess the capacity of high absorptivity of body fluids, usage within the human body typically invites disadvantages beyond advantages realized by low cost and high absorptivity. Thus, artificial foams such as polyurethanes of the prior art have received limited practical acceptance by the medical, dental and government regulatory agencies when proposed for internal usage in the human body. There is especially a disadvantage of such foams.